USC's Department of Public Safety issued alerts asking students to stay away from the area, stay indoors and avoid opening the door to strangers.

In a statement later, USC student affairs vice president Michael Jackson warned students to be vigilant at social events, reminding them that only USC students and guests with student IDs were allowed at campus parties.

In 2008, USC sprinter Bryshon Nellum was shot in the leg three times at a Halloween party just off the campus.

He recovered and won a silver medal in the 4 x 400m relay at the London 2012 Olympics.

The latest shooting comes just months after 12 people were killed and 58 injured in a July shooting at a Batman film screening in Aurora, Colorado.